ath9k_htc: Fix memory leak on WMI event handler

ath9k_wmi_ctrl_rx is racy with ath9k_wmi_tasklet on event notification
due to which the wmi_skb may be overwritten which leads to memory leak.

Signed-off-by: Rajkumar Manoharan <rmanoharan@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/ath/ath9k/wmi.h b/drivers/net/wireless/ath/ath9k/wmi.h
index a0bf857..ac61074a 100644
--- a/drivers/net/wireless/ath/ath9k/wmi.h
+++ b/drivers/net/wireless/ath/ath9k/wmi.h
@@ -31,10 +31,6 @@
 	__be16 seq_no;
 } __packed;
 
-struct wmi_swba {
-	u8 beacon_pending;
-} __packed;
-
 enum wmi_cmd_id {
 	WMI_ECHO_CMDID = 0x0001,
 	WMI_ACCESS_MEMORY_CMDID,
@@ -104,7 +100,7 @@
 	u32 cmd_rsp_len;
 	bool stopped;
 
-	struct sk_buff *wmi_skb;
+	u8 beacon_pending;
 	spinlock_t wmi_lock;
 
 	atomic_t mwrite_cnt;